A generally known disposable diaper comprises an absorbent part for covering the wearer's crotch, formed by sandwiching an absorbent core between a top sheet and a back sheet, a pair of ear parts projecting in opposite directions from the side edges of one longitudinal end portion of the absorbent part so as to lap around the wearer's waist, and two fastening means provided on the side edges of the ear parts, respectively. When using this disposable diaper, the disposable diaper is put on the wearer in an ordinary manner, and then the fastening means are attached to portions of the absorbent part lapping around the waist, on the opposite sides of the fastening means, respectively, to hold the disposable diaper on the wearer. When thus put on the wearer, the disposable diaper must fit to the wearer's waist and legs so that any spaces through which liquid excrements will leak may not be formed between the disposable diaper and the wearer's waist and legs. When putting the disposable diaper provided with the fastening means provided on the side edges of the ear parts, respectively, on the wearer, it is difficult to concentrate the tensile forces applied to the absorbent part by the fastening means effectively on portions of the absorbent part lapped around the wearer's waist and legs; that is, spaces are formed around the wearer's legs if the disposable diaper is fitted to the wearer's waist, or spaces are formed around the wearer's waist and the disposable diaper cannot lap fitly around the wearer's waist if the disposable diaper is fitted to the wearer's legs.
Various improvements have been proposed to solve such problems and to improve the fit of a disposable diaper to the wearer's waist and legs. Techniques for improving the fit of a disposable diaper to both the waist and the legs are disclosed in U.S. Pat. No. 4,680,030 to Aled, et al., U.S. Pat. No. 4,826,499 to Ahr and U.S. Pat. No. 4,937,887 to Schreiner, which use two pairs of fastening means attached to a pair of ear parts projecting in opposite directions from a portion of the disposable diaper to be lapped around the waist, respectively. These prior art disposable diapers, however, require troublesome work for handling the tow pairs of fastening means and there is room for improvement in those prior art disposable diapers.
Techniques eliminated such a disadvantage are disclosed in U.S. Pat. No. 4,911,702 to O'Leary and U.S. Pat. No. 4,857,067 to Wood, which use two fastening means attached to two ear parts, respectively, and capable of effectively concentrating the tensile forces applied thereto on portions of the absorbent part lapped around the waist and the legs. However, these techniques mention nothing about the positions of the two fastening means to distribute the tensile forces applied to the two fastening means effectively and directly around the waist and the legs and about the positions of the two fastening means to distribute the tensile forces applied to the two fastening means around the waist and the legs at an intentionally determined distribution ratio.
A disposable diaper disclosed in, for example, Japanese Utility Model Laid-open (Kokai) No. 59-73305 has a main part, ear parts projecting in opposite directions from the side edges of the main part, respectively, and two fastening means attached to the side edges of the ear parts parallel to the longitudinal axis of the main part respectively, so as to extend obliquely to the transverse edge of the longitudinal end of a portion of the main part on the back side to distribute the tensile forces applied to the main part by the two fastening means effectively around the waist and the legs. Although the two fastening means are attached to the ear parts, respectively, so as to extend obliquely to the transverse edge of the longitudinal end of a portion of the main part on the back side, the fastening means are pulled involuntarily in a direction perpendicular to the side edges of the ear parts because the fastening means are attached to the side edges of the ear parts parallel to the longitudinal axis of the main part, respectively, and, consequently, the tensile forces applied to the main part by the two fastening means cannot be properly distributed around the waist and the legs at an intended distribution ratio.